Tax breaks could be damaging the environment, according to new research.
An ESRI study claims some Government measures are leading people to be less environmentally-friendly behaviour.
It says closing the difference in tax rates between petrol and diesel cars, for example, could cut CO2 emissions by 1%.
Edgar Morgenroth, who carried out the research, said: "First of all the study suggests that when we are making changes to the tax system we should consider the environmental implications.
"Secondly, it shows that there are measures out there that could easily be taken to affect some of the changes that we are looking at."